During the next year we will characterize the B cell antigenic profile on a panel of cultured human lymphoid cells, of frozen cells from patients with chronic lymphocytic leukemia and of enriched populations of B peripheral lymphocytes from normal donors. Our method is to test these cells with a large selection of antisera to B cell antigens previously submitted to the VI International Histocompatibility Testing Workshop. Ongoing efforts to produce specific xenoantisera to B cell antigens will continue. The specificity of these xenoantisera will be compared with that of alloantisera to B cell antigens. Establishing the genetic controls over cell membrane structures that react with xenoantisera and the function of such structures in susceptibility to viral infection will follow. How humoral immunity to B cell antigens influences kidney allograft survival will be investigated and correlated with the effect of antibodies to B cell antigens on cellular immune recognition phenomenon.